The U.N. Security Council will soon vote on a resolution imposing tougher sanctions on North Korea for its recent intercontinental ballistic missile tests, diplomats said Saturday.

The U.S.-drafted resolution aims to cut North Korea's export revenue by one-third to $1 billion a year, according to news reports.

"We tabled a U.N. Security Council Resolution and hope for adoption as soon as possible," a U.S. official told Yonhap on the condition of anonymity.

After lengthy negotiations, the U.S. reached a deal on related measures with China, the top trading partner and ally of the North, they said. Russia seems to have approved the proposal, a South Korean diplomatic source said.

The vote -- scheduled to start at 3 p.m. on Saturday (New York time), when it will be 4 a.m. on Sunday in Seoul -- is widely expected to pass the council as Washington struck an agreement with Beijing and probably Moscow.

Securing consent from China and Russia is key as they are two of the five permanent veto-wielding members of the U.N. Security Council. The binding resolution calls for a ban on the North's exports of coal, iron, lead and seafood.

It will also restrict new joint ventures with North Korean companies and prohibit additional permits for North Korean workers abroad.

As the sanctions are designed to deprive the Kim Jong-un regime of financial resources to develop its nuclear and missile programs, restrictions on supplies of oil will be excluded.

Both China and Russia, which border North Korea, do not want the deepening of humanitarian crises in the communist neighbor.

On Wednesday, the U.S. slapped separate sanctions against the North. The North, which is already under numerous sanctions for its five nuclear tests, fired two intercontinental ballistic missiles in July.

In the previous resolutions against Pyongyang adopted last year, the council set export caps on coal, the country's main trade item.

Through the planned ban, the North is expected to lose $400 million in its annual export revenue, the Voice of America (VOA) quoted a U.N. diplomat as saying.

The new resolution also designates nine North Korean individuals and four entities for asset freezes and travel bans, the VOA said. (Yonhap)